Introduction: Over 400,000 Americans are intubated emergently annually, and prior data suggests that 2-5% of them have recall of the period of peri-intubation paralysis. Awareness is associated with long-term post-traumatic stress disorder, and rocuronium use is a significant risk factor. The objective of this study was to measure real-time bispectral index (BIS) in patients being intubated in the ICU, during the period of neuromuscular blockade.
Methods: We conducted a single-center, observational ICU-based study of adults intubated between July 2024 and January 2025. We measured continuous BIS measurements from immediately before rapid sequence induction until serial train-of-four measurements had return of 4/4 twitches. We defined “risk of awareness” as BIS score>60 for at least 4 minutes during paralysis. We reported data using descriptive statistics in aggregate, and we defined awareness based on the modified Brice questionnaire by a panel of 3 blinded adjudicators.
Results: We enrolled 54 participants, and most were enrolled with etomidate (50%) and rocuronium (89%). The median time to post-intubation sedation was 7.0 min (interquartile range [IQR] 3.3-16.0 min). A total of 25 participants (46%) had BIS score>60 for greater than 4 minutes during neuromuscular blockade, and the median duration of BIS>60 was 19.5 min (IQR 15.00-37.25). Of 41 participants interviewed after extubation, 1 (2%) reported definite awareness and an additional 2 (5%) reported possible awareness.
Conclusions: In patients being intubated with neuromuscular blockade in the ICU in a single-center case series, 46% had BIS>60 for at least 4 minutes. These patients may have increased risk of awareness during peri-intubation paralysis, and EEG-based tools represent an attractive target for sedation titration during paralysis. Future work will better elucidate the role of surrogate markers of awareness on improved peri-intubation sedation management and reduced risk of peri-intubation awareness.
